Answer:
A. Monasteries
Step-by-step explanation:
Monasteries is a complex building that's usually occupied by monks and nuns. Traditional Christians do not allow both monks and nuns to be married, so most of them devoted their live by living secluded away from the rest of societies.
Typical monasteries usually very busy, just like any workplace. Most of the people who live there were assigned with specific jobs that they need to do for missionaries purposes (such as copying the text from holy scriptures, preparing voluntary missions, creating religious artworks, etc)